Rail-guided transport system with transport vehicles

ABSTRACT

A track (rail)-guided transport system has at least one track of bearing and rail-guiding members on which is run at least one transport vehicle which has means for self-automated continuous movement along the track and to which energy is transmitted contactlessly from a primary circuit laid down along the track. The transport vehicle is designed as a carrier vehicle ( 2 ) for at least one satellite vehicle ( 3,9 ) used to transport goods and has a satellite track section for positioning and parking the satellite vehicle ( 3,9 ). The satellite track section can be brought into alignment by positioning the carrier vehicle ( 2 ) flush to satellite tracks arranged along its track, perpendicular thereto. Energy from a primary circuit laid down along the satellite tracks ( 7,8 ) is transmitted contactlessly to the satellite vehicle ( 3,9 ) equipped with means for automated locomotion. The satellite vehicle ( 3,9 ) and the carrier vehicle ( 2 ) have processor capacity and means for wireless transmission of information between them and/or with a central processing unit.

TECHNICAL FIELD

The invention concerns a therefor-track rail-guided transportationsystem with at least one travel path of carrying and track-guidingelements, with at least one transport vehicle for goods which has meansfor moving along the travel path and receives contactless power from aprimary circuit laid along the line.

BACKGROUND OF THE INVENTION

It is already known to transmit contactless power to a vehicle. Themagazine Elektric 34, 1980, H. 7 describes an arrangement for inductivepower transmission to a hauling engine in a mine. This arrangementcontains double lines which are laid along the ceiling of the minetunnel. Ferrite bodies with secondary windings move between the doubleline; they are connected to the hauling engine and supply power to thedrives and other consumers.

A device for contactless power transmission to a track-guided vehicle(PCT-GB 92/00220) is also known. A double line is secured toelectrically nonconducting posts. A ferrite core that is installed on avehicle can move along the double line and carries a secondary windingfor feeding power to the vehicle. The double line receives alternatingvoltage in the KHz range.

Also known are high shelves for stacking goods or pallets with goods.Lifting movers travel between a receiving and discharging place and theshelves, to fill and empty the shelves with goods or pallets.

SUMMARY OF THE INVENTION

The invention is based on the problem of developing a track-guidedtransportation system which can be assigned transportation tasks in asimple manner, and which is also in a position to quickly carry outtransportation tasks to loading and unloading areas which are farremoved from each other.

This objective is achieved with a transportation system of the kinddescribed in the beginning, in that the transport vehicle is designed asa carrier for at least one satellite vehicle for transporting goods, andhas a satellite travel section for positioning and parking the satellitevehicle, that by positioning the carrier vehicle along its travel path,the travel section can be aligned flush and crosswise to these satellitetravel sections, that power is transmitted in a contactless manner froma primary circuit laid along the satellite travel paths to the satellitevehicle which is equipped with means for moving it, and that at leastone satellite vehicle and the carrier vehicle have processingcapabilities and means for wireless telecommunication between themselvesand/or a central control unit. The transportation system of theinvention is able to carry out transportation tasks in a very flexiblemanner. Even if the carrier vehicle has only one satellite travelsection, the carrier vehicle can cooperate with several satellitevehicles, whereby for example a satellite vehicle is transported to asatellite travel path, while other satellite vehicles carry outtransportation tasks on satellite travel paths, or stand by loaded withgoods until the carrier vehicle has brought its satellite vehicle withits goods to a selected travel section, and immediately proceeds totravel to the travel section of the other satellite vehicle in order toreceive it and transport it to a new destination. The path beingtraveled or the target travel sections are selected by a respectivetransporting program, whose destination data come from a centralprocessor which is designed e.g. as a group of input units. Asignificant advantage of the system of the invention can therefore beseen in that the carrier vehicle does not need to wait in a stand-byposition while the satellite vehicle carries out a transportation taskswith goods. The result is a considerable increase in the transportationoutput, as opposed to a system in which a carrier vehicle must wait fora satellite until it has gone to receive or discharge goods and hasresumed its position on the carrier vehicle.

A preferred configuration provides for at least two travel paths for thecarrier vehicle in two superimposed planes with corresponding transversesatellite travel paths, and an elevator for the carrier vehicle at leastat one end of the travel path.

This device can significantly increase the transportation output and thecapacity of storing goods, since the carrier vehicle and satellitevehicles can be active in different planes by controlling thecommunication link. In this case the activity also includes the stand-byposition of the carrier vehicle or satellite vehicle at a pickup ordischarge place.

It is useful if the at least one satellite vehicle is designed to pickup, transport and deposit pallets. Such a configuration is particularlysuited for shelves, e.g. high shelves.

The power is transmitted inductively to the carrier vehicle and to thesatellite vehicle(s), particularly via the middle frequency. It istherefore useful to select a transmission device that has lowinductance, even in long travel paths. It is useful if such a deviceincludes a stationary primary circuit designed as a long linearrangement, which is connected to the middle frequency and is alsoarranged on the carrier vehicle along the travel path of the carriervehicle and the satellite vehicle, and each comprises a ferritetransformer head arranged on the carrier vehicle and the satellitevehicle, and a secondary winding which encloses the ferrite core and isinductively coupled to the primary circuit. The line arrangement of theprimary circuit contains an outer conductor designed as an almost closedhousing, and a middle conductor located approximately in the center ofthe housing, in which a current of the same magnitude flows in theopposite direction, where the middle conductor is enclosed by theU-shaped ferrite core. This device allows power to be transmitted acrossair gaps in the centimeter range, with relatively low effort and goodefficiency in the presence of low self-inductance, for thetransportation of loads. The current is distributed over two outerwalls, which still provides a relatively large transmission crosssection, despite the skin effect.

Advantageously the U-shaped ferrite core has windings on both legsopposing the primary conductor, whose height corresponds approximatelyto the height of the primary conductor and is between 0.3 times and 0.5times the total height of the U-shaped core. The height of the primaryconductor in relation to the average width of the magnetic flux in theconductor area is chosen so that the transmitted power is at maximum.

For the most uniform distribution of the current, it is furthermoreadvantageous if the outer walls of the housing, which are opposite themiddle conductor, form an arch in as wide a current-carrying area aspossible. The cross sections of the outer and middle conductors and theaverage cross section of the magnetic flux can be configured, and thesize relationships can be designed, so that a minimum of electricaldissipation takes place. A condenser is installed on the secondarywinding, parallel to the load resistor; said condenser supplies themagnetization current to produce the magnetic flux density in the airgap of the ferrite core. The secondary winding is also switched inseries with a condenser which compensates for the inductive voltage dropin the control inductance of the transformer head.

Communications are preferably transmitted in wireless form to thecarrier and the satellite vehicles respectively via lines laid along thetravel paths. Such a contactless arrangement for transmittinginformation enables a high transmission quality that is mostly free ofelectromagnetic interference. The line is preferably a coaxial cablewith openings, which interacts with a patch antenna located on thecarrier vehicle or on the satellite vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail in the following by meansof embodiments illustrated by drawings which provide further details,features and advantages, wherein:

FIG. 1 is a schematically perspective view of a track-guidedtransportation system;

FIG. 2 is a schematic lateral view with a partial cross section of acarrier vehicle and a satellite vehicle of the transportation systemillustrated in FIG. 1;

FIG. 3 is a schematic frontal cross section of a satellite vehicle ofthe transportation system according to FIG. 1;

FIG. 4 is a device for the contactless transmission of power,track-guidance and information;

FIG. 5 is a longitudinal cross section or top view of a device for thecontactless transmission of power with an open coaxial conductor.

BEST MODE FOR CARRYING OUT THE INVENTION

As seen in FIG. 1, a track-guided transportation system has at least onetransport vehicle which can move along a travel path 1, and is designedas a carrier vehicle 2 for at least one satellite vehicle 3. Thesatellite vehicle 3 is intended for the receiving, transporting anddischarging of goods 4. Two satellite travel sections 5, 6, which extendcrosswise to the travel path 1, have carrying and track-guidingelements. The travel path 1 has carrying and guiding elements as well,which are described in more detail below. Both the carrier vehicle 2 andthe satellite vehicle 3 are equipped with means for track-guiding ortrack-holding, and for moving.

Satellite travel paths 7, 8 are located next to the travel path 1 at theheight of the satellite travel sections 5, 6. The travel sections 5, 6can be aligned flush with the satellite travel paths 7, 8 by positioningthe carrier vehicle 2 accordingly. This can take place e.g. by means ofsensors on the carrier vehicle 2 or on the travel paths 5, 6. Once atravel path 5 or 6 is aligned flush with the respective travel path 7,8, the satellite vehicle 3 can change over from the carrier vehicle 2 tothe travel path 7 or 8, or conversely from a travel path 7, 8 to thecarrier vehicle 2. FIG. 1 illustrates the satellite vehicle 3 andanother satellite vehicle 9. The representation of two satellitevehicles should not be assumed to be limiting.

Primary circuits are laid respectively along the travel path 1 and thesatellite travel paths 7, 8, and power is wirelessly transmitted fromthem to operate the carrier vehicle 2 and the satellite vehicles 3, 9.The travel sections 5, 6 also have such primary circuit sections tosupply power to the satellite vehicles 3, 9 for changing from thecarrier vehicle 2 to the travel path 7, 8 and vice versa. Both thecarrier vehicle 2 and the satellite vehicles 3, 9 are equipped withcircuits having processing capabilities, which enables them to record atleast one control program. Furthermore the carrier vehicle 2 and thesatellite vehicles 3, 9 are each equipped with a communicationinterface, where means are provided for the wireless transmission ofinformation between the carrier vehicle 2 and the satellite vehicle 3,9, and possibly to a central unit.

As seen in FIGS. 1 and 2, the carrier vehicle 2 comprises a drivingpart, which is schematically illustrated in a lower plane together witha track-guidance and sliding function. This lower plane, together withthe uppermost plane, which is provided for storing the satellitevehicles 3 with their goods, forms a type of track-guided carriage. Aninformation plane complements this carriage into a self-sufficientsystem. This information plane receives and sends data from and to thesatellite vehicles, and from and to a fixed station which contains atransmitter and a receiver for the exchange of information, and is ableto transmit and receive data as well. In addition, the carrier vehicle 2and the satellite vehicles each have a data processor which can operateactuators and sensors. This makes it possible for example to carry out amagnetic track-guidance and gravity compensation with gap control. Theadjustment of the drives takes place in accordance with the specifiedtransportation tasks, which are issued e.g. by the fixed station.Furthermore the distance between individual carrier vehicles iscontrolled by the exchange of information between the vehicles, so thatno collision can take place when several carrier vehicles move on thesame travel path 1. The uppermost plane for storage and input and outputcan be set up in many ways, for example with a lifting element or aroller conveyor.

FIG. 2 shows that the carrier vehicle runs on rollers 10 and on rails 11of the travel path 1 for example, where the drive is brought about withthe help of a motor 12. The power for driving the motor 12 and otherservo drives is provided by a contactless power transmission. This ismade clear in FIG. 4, therefor which illustrates a rail 11 whose topside forms the track for the rollers 10. The top of the rail 11 has anL-shaped angle. The angled part covers a middle conductor 13 held by abridge 14, which is attached to the underside of the angled section ofthe rail 11. The middle conductor 13 is supplied by a not illustratedmiddle frequency generator. The contactless transmission of power takesplace by means of a transformer head 15, which has a winding W2 and isattached in the same way to the carrier vehicle 2 and to the satellitevehicles 3, 9. The core of the transformer head 15 is made of a ferritematerial. The middle conductor 13, which protrudes into the transformerhead 15, is part of an E-shaped arrangement that also includes the outerconductor 13 a.

A slotted coaxial cable 25 is attached to the rail for transmission ofthe information. The coaxial cable 25 is connected to a fixedtransmitting and receiving station. A patch antenna 19 is attached tothe carrier vehicle 2 and is connected inside the carrier vehicle 2 to amobile station. The transmission of the information between the fixedstation, the carrier vehicle 2 and the satellite vehicles 3, 9 can alsotake place via radio.

To reduce the height of the rail, the primary element which is E-shapedtowards one side, can be rotated 90° with respect to the arrangementillustrated in FIG. 4, i.e. horizontally. FIG. 5 illustrates the powertransmission principle of the coaxial conductor arrangement which isopen on one side.

Inside the transformer head 15, the U-shaped ferrite core envelops themiddle conductor 13 and conducts the magnetic flux Φ through thesecondary winding W₂. One end of the middle conductor 13 is supplied bya middle frequency generator so that it can conduct the current I₁. Itis connected to the housing at the end E, which is removed from thesupply source. Because of the symmetrical arrangement, the current isdivided here into two partial currents I_(1/2) of the same magnitude,and flows back over the housing to the middle frequency generator MFG.

Because of the current displacement taking place at high frequencies inmassive conductors such as the U-shaped housing (made of aluminum forexample), often also called the skin effect, the current is notuniformly divided in the housing walls, but penetrates from the insideinto the housing walls in accordance with the penetration depth δ_(E) .At 25 kHz and with aluminum, the penetration depth is about 0.5 mm. Noris the current uniformly divided in the inner periphery of theU-profile, but flows primarily in the areas of the largest magneticfield strengths.

FIG. 3 schematically illustrates a satellite vehicle 3 or 9 from thefront. The contactless transmission of power, as explained in greaterdetail in FIGS. 4 and 5, is supplied to the satellite vehicle 3 from theunderside. Each travel path 7, 8 contains rails 18, 19 on which thewheels 20, 21 of the satellite vehicle 3 roll. The rails 18, 19 arearranged at a distance from the ground on not illustrated supports andhave Z-profiles, because they are simultaneously designed as depositsurfaces for pallets 22, which are carried by lifting platforms 23 ofthe satellite vehicles 3, 9. The wheels 20, 21 are supported by thelower angled ends of the Z-profiles, while the upper angled ends facethe outside of the rails. The underside of the rail 19 has a carrier 24attached to it, on which the E-shaped primary circuit with the middleconductor 13 and the outer conductor 14 are located. A not illustratedtransformer head extends from the underside of the satellite vehicle 3,9 into the primary circuit. In principle, the construction of the devicefor transmitting power corresponds to the one illustrated in FIGS. 4 and5.

The satellite vehicles are able to carry out transportation taskssimultaneously with the carrier vehicle 2, i.e. satellite vehicles cantransport goods on the travel paths 7, 8 while the carrier vehicle 2 isalready moving satellite vehicles to other travel paths. With a liftinginstallation, the device illustrated in FIGS. 1-3 can be arranged inseveral planes. For that reason the system is particularly suited forhigh shelf storage. In that case the satellite vehicles can be active inseveral planes by means of the lifting installation, i.e. loads or goodscan be transported from one plane to another with the help of carriervehicles. Depending on the work requirement, several satellites canoperate on one carrier vehicle 2. The system makes it possible torapidly switch pallets from one storage area to another discharge area.Beyond that, the high speed of the vehicles is possible because nohindrances are caused by cables.

What is claimed is:
 1. A track-guided transportation system with atleast one travel path of carrying and track-guiding elements, with atleast one transportation vehicle that comprises at least oneself-activated powered motor providing movement along the travel path,and to which power is transmitted in a contactless manner from a primarycircuit laid along the travel path, wherein: the transport vehicle isdesigned as a carrier vehicle (2) for at least one satellite vehicle (3,9) for the transportation of goods, and has a satellite travel sectionfor positioning and parking the satellite vehicle (3, 9); the satellitetravel section can be oriented flush by positioning the carrier vehicle(2) crosswise along its travel path; the satellite vehicle (3, 9), whichcomprises at least one self-activated powered motor providing movement,receives power in a contactless manner from a primary circuit laid alongthe satellite travel paths (7, 8); and at least one satellite vehicle(3, 9) and the carrier vehicle (2) include processing capabilities andtransmitters for the wireless transmission of information betweenthemselves and/or to a central unit which enable the satellite vehicle(3,9) and the carrier vehicle to move in a flexible manner directed by atransporting program.
 2. A transportation system as claimed in claim 1,characterized in that at least two travel paths are provided for thecarrier vehicle in two superimposed planes with corresponding crosswisesatellite travel paths, and an elevator is provided at least at one endof the travel paths.
 3. A transportation system as claimed in claim 2,characterized in that at least one satellite vehicle is designed forreceiving, transporting and unloading pallets.
 4. A transportationsystem as claimed in claim 1, characterized in that at least onesatellite vehicle is designed for receiving, transporting and unloadingpallets.
 5. A track-guided transportation system with at least onetravel path of carrying and track-guiding elements, with at least onetransportation vehicle that comprises at least one self-activatedpowered motor providing movement along the travel path, and to whichpower is transmitted in a contactless manner from a primary circuit laidalong the travel path, wherein: the transport vehicle is designed as acarrier vehicle (2) for at least one satellite vehicle (3, 9) for thetransportation of goods, and has a satellite travel section forpositioning and parking the satellite vehicle (3, 9); the satellitetravel section can be oriented flush by positioning the carrier vehicle(2) crosswise along its travel path; the satellite vehicle (3, 9), whichcomprises at least one self-activated powered motor providing movement,receives power in a contactless manner from a primary circuit laid alongthe satellite travel paths (7, 8); and at least one satellite vehicle(3, 9) and the carrier vehicle (2) include processing capabilities andtransmitters for the wireless transmission of information betweenthemselves and/or to a central unit which enable the satellite vehicle(3,9) and the carrier vehicle to move in a flexible manner directed by atransporting program, characterized in that at least two travel pathsare provided for the carrier vehicle in two superimposed planes withcorresponding crosswise satellite travel paths, and an elevator isprovided at least at one end of the travel paths, and characterized inthat at least one satellite vehicle is designed for receiving,transporting and unloading pallets, and also characterized in that thepower is electromagnetically transmitted at a frequency from the primarycircuit to the carrier vehicle (2) and to the satellite vehicles (3, 9).6. A transportation system as claimed in claim 5, characterized in thatthe primary circuit is designed respectively as a long line arrangement,it is connected to the frequency source and is arranged along the travelpath (1) of the carrier vehicle (2) and along the satellite travel paths(7, 8), that a ferrite transformer head (15) each is located on thecarrier vehicle (2) and the satellite vehicles (3, 9), and a secondarywinding encloses the ferrite core and is inductively coupled to theprimary circuit.
 7. A track-guided transportation system with at leastone travel path of carrying and track-guiding elements, with at leastone transportation vehicle that comprises at least one self-activatedpowered motor providing movement along the travel path, and to whichpower is transmitted in a contactless manner from a primary circuit laidalong the travel path, wherein: the transport vehicle is designed as acarrier vehicle (2) for at least one satellite vehicle (3, 9) for thetransportation of goods, and has a satellite travel section forpositioning and parking the satellite vehicle (3, 9); the satellitetravel section can be oriented flush by positioning the carrier vehicle(2) crosswise along its travel path; the satellite vehicle (3, 9), whichcomprises at least one self-activated powered motor providing movement,receives power in a contactless manner from a primary circuit laid alongthe satellite travel paths (7, 8); and at least one satellite vehicle(3, 9) and the carrier vehicle (2) include processing capabilities andtransmitters for the wireless transmission of information betweenthemselves and/or to a central unit which enable the satellite vehicle(3,9) and the carrier vehicle to move in a flexible manner directed by atransporting program, characterized in that the power iselectromagnetically transmitted at a middle frequency from the primarycircuit to the carrier vehicle (2) and to the satellite vehicles (3, 9).8. A track-guided transportation system with at least one travel path ofcarrying and track-guiding elements, with at least one transportationvehicle that comprises at least one self-activated powered motorproviding movement along the travel path, and to which power istransmitted in a contactless manner from a primary circuit laid alongthe travel path, wherein: the transport vehicle is designed as a carriervehicle (2) for at least one satellite vehicle (3, 9) for thetransportation of goods, and has a satellite travel section forpositioning and parking the satellite vehicle (3, 9); the satellitetravel section can be oriented flush by positioning the carrier vehicle(2) crosswise along its travel path; the satellite vehicle (3, 9), whichcomprises at least one self-activated powered motor providing movement,receives power in a contactless manner from a primary circuit laid alongthe satellite travel paths (7, 8); and at least one satellite vehicle(3, 9) and the carrier vehicle (2) include processing capabilities andtransmitters for the wireless transmission of information betweenthemselves and/or to a central unit which enable the satellite vehicle(3,9) and the carrier vehicle to move in a flexible manner directed by atransporting program, characterized in that the primary circuit isdesigned as a long line arrangement, it is connected to a frequencysource and is arranged along the travel path (1) of the carrier vehicle(2) and along the satellite travel paths (7, 8), that a ferritetransformer head (15) is located on the carrier vehicle (2) and thesatellite vehicles (3, 9), and a secondary winding encloses the ferritecore and is inductively coupled to the primary circuit.